Towed body for representing a flying target

ABSTRACT

The invention relates to a tow body for the representation of flying targets by means of infrared flares, the infrared flares being situated at the rear of the tow body and being ejectable from the tow body and capable of being pulled by the tow body by means of towing cables during the burning time. According to the invention, a section of the towing cable ( 6 ) situated between the IR-flare-side cable linkage ( 2 ) and the tow-body-side cable linkage ( 5 ) is sewn onto a woven flap ( 1 ), this connection being releasable during the reel-off operation of the towing cable ( 6 ).

[0001] The invention relates to a tow body for representing a flying target according to the preamble of claim 1.

[0002] In manned flying target representation, tow bodies have been equipped for some time with infrared (IR) flares and have been used for training and bombarding by missiles equipped with infrared (IR) guidance heads. These IR flares can be obtained on the market with a wide spectrum of activity and can be fixedly fastened to the rear of the tow body.

[0003] For reasons of reusability of the tow bodies, the IR flares can also be pulled on a reel-off towing cable behind the tow bodies, whereby, in the event of a hit of the missile, only the IR flare and not the tow body will be lost. Such a tow body for representing a flying target is known from German Patent Document DE 198 14 936 C1. Each IR flare is situated in an ejection unit and is driven out toward the rear during the ignition, in which case a towing cable is reeled off. From Patent Document OS 27 50 582, a cable package in two mutually sewn-together woven flaps is known for this purpose, whereby it is prevented that, knottings or entanglements of the towing cable occur during the reel-off operation of the towing cable.

[0004] In this case, the IR flare reeled-off by means of the towing cable is highly accelerated as a result of the ram pressure applied at high flying speeds of approximately 150 m/s. The IR flare falling into the towing cable is highly braked in such a manner that the resulting high forces may lead to a tearing-off of the towed IR flare. In addition, an overloading of the mechanical suspensions of the towing cable at the tow body may occur. The polypropylene cables normally used for this purpose, which have considerable damping characteristics and a high tensile stressing capacity, cannot withstand this load.

[0005] It is problematic that the IR flare, which had been ignited during the ejection, during the entire reel-off operation of the towing cable, repeatedly briefly touches the towing cable with its hot flame. This may damage the towing cable and impair the damping characteristics of the cable.

[0006] It is an object of the invention to provide a tow body of the above-mentioned type by means of which it is possible to eject an ignited IR flare without damaging the towing cable or its mechanical suspension.

[0007] This object is achieved by means of the object of claim 1. The subclaims relate to advantageous further developments of the invention.

[0008] According to the invention, a section of the towing cable situated between the IR-flare-side and the tow-body-side cable linkage is sewn onto a woven flap by means of a connection which can be opened up during the reel-off operation of the towing cable. In particular, the woven flap may be a woven polyamide flap.

[0009] By means of the invention, the IR flare ejected from the tow body is braked during the reel-off operation of the towing cable, whereby the force peaks, which result in a tearing-off of the towing cable, particularly during the final braking, are avoided.

[0010] During the reel-off operation of the towing cable, the ejected IR flare encounters an almost constant force in the direction of the tow body. This counterforce results from the releasable connection between the towing cable and the woven flap which is opened up by means of the force driving the ejected IR flare. The force driving the IR flare results from the acceleration experienced by the ejected IR flare because of the high applied ram pressure. The effective driving force upon the IR flare is therefore the result of the difference between the applied forces, in which case, the force (counterforce) in the direction of the tow body should be lower than the force driving the IR flare. Thus a continuous and constant reeling-off of the towing cable is achieved.

[0011] It is another advantage of the invention that, as a result of the described measures, it is prevented that, during the reel-off operation, the ejected ignited IR flare comes in contact with the towing cable. Damage to or a possible tearing-off of the towing cable are therefore avoided.

[0012] By means of the invention, an effective reeling-off of the towing cable is achieved. It is another advantage that the connection according to the invention between the towing cable and the woven flap can be produced at reasonable cost and can be handled easily.

[0013] The towing cable can advantageously be a kevlar-coated polypropylene damping cable. By means of the kevlar coating, it is possible to subject the damping cable at maximal breaking elongation values briefly to a high temperature-caused stress without damaging the cable.

[0014] The towing cable can advantageously be applied and sewn onto the woven flap in a serpentine-shape. This construction was found to be particularly effective during the flying tests carried out by the applicant. A shortening of the seam length to half the cable length to be sewn can be achieved in that, in another advantageous embodiment of the invention, only those cable sections which extend against the pulling direction of the IR flare are sewn to the woven flap. In this case, the direction of the respective cable sections is defined by the towing cable extending from the tow body to the IR flare.

[0015] This results in further manufacturing-related advantages. The seam thickness as well as the used sewing yam can be adapted to the required operating conditions (such as the speed of the tow body or the weight of the IR flare).

[0016] In order to avoid a disturbance of the towing flight behavior by a flapping of the woven flap, in another advantageous embodiment of the invention, a tent-shaped eye is arranged on the woven flap on the towing body side. A retaining loop for the woven flap is guided through this tent-shaped eye. This retaining loop is fixedly connected, for example, sewn to the towing cable. A towing cable loop, which is guided through this retaining loop, is connected, for example, by means of a stitch, with the woven flap.

[0017] As a result of these measures, it is achieved that, during the reel-off operation, the woven flap is held on the tow body side and a tearing-out of the towing cable from the woven flap takes place only on the IR flare side. After the conclusion of the reel-off operation—with the entire sewn connection being torn out—, the tow-body-side cable piece is tensioned, whereby the stitch, which fixes the towing cable loop on the woven flap, is torn off. Now, the towing cable loop is unlooped from the retaining loop because of the tension upon the towing cable. Subsequently, an unlooping of the retaining loop from the tent-shaped eye takes place.

[0018] The connection between the towing cable and the woven flap is now completely opened up, and the woven flap is dropped.

[0019] In order to achieve an optimal tearing-out of the towing cable from the woven flap, the woven flap can advantageously be sewn up to be a hose, the sewn-up towing cable extending in the interior of the hose. The towing cable loop is mounted on the exterior wall of the hose.

[0020] Additional advantages are indicated by the resulting improved flying characteristics of the woven flap.

[0021] The hose can be rolled together without any problems and, by way of a small woven bag, can be mounted as a round pack of a diameter of approximately 25 mm and a length of approximately 50 mm by means of an adhesive strip on the IR flare. Naturally, the adhesive strip will tear off after the ejection of the IR flare.

[0022] In the following, the invention will be explained in detail by means of drawings.

[0023]FIG. 1 is a top view of an embodiment according to the invention of a woven flap with a sewn-on towing cable;

[0024]FIG. 2 is a rear view of a woven flap folded together along a folding line A-A, with a tent-shaped eye, a retaining loop and a towing cable loop.

[0025]FIG. 1 illustrates an embodiment according to the invention of a woven polyamide flap 1, onto which a kevlar-coated polypropylene damping cable is sewn. The damping cable 6 is sewn onto a surface of the woven flap 1 in a serpentine shape and approximately over the entire surface of the flap in one plane. The sewing-together takes place on cable sections 3 between successive deflections.

[0026] A cable section 2 for the IR-flare-side towing cable linkage and a cable section 5 for the tow-body-side towing cable linkage extend out of the sewn plane. The cable sections 2, 5 are parallel-constructed extensions of the sewn cable sections and are situated on opposite sides of the woven flap 1. Cable section 2 of the IR-flare-side cable linkage extends in the sewn plane of the woven flap 1. Cable section 5 of the tow-body-side cable linkage extends on the rearward side of the woven flap 1 facing away from the viewer.

[0027] For simplifying the production, the sewing of the towing cable takes place in those cable sections 3 in which the towing cable extends in the pulling direction. As a result, it is achieved that, by the ripping-out of the sewing, a constant counterforce is applied to the IR flare, whereby a tearing-off of the towing cable is prevented during the final braking of the IR flare.

[0028] On the IR flare side, the towing cable 6 is not sewn up to the first deflection. This is adjoined by alternately sewn-on and not-sewn-on cable sections 3. The cable section 3 which follows the last deflection and points in the direction of the IR-flare-side cable linkage is sewn to the woven flap 1. Subsequently, the towing cable is guided from the sewn plane of the woven flap 1 on its rearward side and there to the opposite side of the woven flap 1 in the direction of the tow-body-side cable linkage. On the tow body side, a retaining loop 4 is mounted on the towing cable, which retaining loop 4 has the purpose of connecting the woven flap 1 during the reel-off operation tightly with the tow-body-side cable linkage. The retaining loop 4 can, for example, be firmly sewn to the towing cable 6.

[0029] The broken lines 7 are seam lines for the fold-over lugs which, during the flight, prevent a fraying of the woven flap 1 and ensure a stabilization of the woven flap 1 in the folded-together condition. The woven flap 1 can be folded over along the folding line A-A.

[0030] In the left-hand representation, FIG. 2 shows a rear view of a woven flap 1 folded together along the folding line A-A (FIG. 1). In this case, the woven flap 1 is sewn together along the upper broken line 8 to form a hose. In the right-hand representation, a lateral view of a tent-type eye 9 is illustrated through which a retaining loop 4 is guided.

[0031] On the surface of the woven flap 1 facing away from the viewer, the towing cable 6 is sewn on and is guided from there, as described above, to the side facing the viewer. There, the towing cable leads from the side of the woven flap 1 facing the IR flare to the side of the woven flap 1 facing the tow body. On the tow body side, a tent-type eye 9 is mounted in the folded-together woven flap hose 1. The diameter of the tent-type eye. 9 is in the range of the diameter of the used kevlar-coated polypropylene cable.

[0032] From the side facing away from the viewer, a retaining loop 4, such as a polypropylene cable, is guided through the tent-type eye (right-hand representation). The portion of the retaining loop 4 situated on the side of the retaining loop facing away from the viewer is guided around the woven flap 1 and, on the tow body side, is connected, for example, sewn at a point P firmly to the towing cable 6.

[0033] A towing cable loop 10 is guided through the retaining loop 4 on the side facing the viewer, which towing cable loop 10 is connected with the woven flap 1 by means of a sewn connection 11 (securing stitch).

[0034] During the reel-off operation, the cable section 12 extending between the last sewn connection (FIG. 1) and the tent-type eye 9 is without tensile stress. The reason is that the pull exercised by the IR flare between the IR-flare-side cable linkage 2 and the tow-body-side cable linkage 5 does not extend by way of the described cable section 12 but by way of the woven flap 1 and the retaining loop guided through the tent-type eye 9. In this case, the towing cable loop 10 is pulled by means of the retaining loop 4 onto the tent-type eye 9 but is not pulled through the latter. The securing stitch 11 here has the purpose of preventing a premature accidental unlooping of the towing cable loop 10 from the retaining loop 4.

[0035] After the conclusion of the reel-off operation, thus after the tearing-out of the entire sewn connection, pull is exercised on the cable section 12 extending between the last sewn connection (FIG. 1) and the tent-type eye 9 (the towing cable will now extend completely outside the woven flap hose 1). The securing stitch 11 is torn off and the towing cable loop 10 is unlooped from the retaining loop 4. Subsequently, the retaining loop 4 unloops from the tent-type eye 9 because the tension force between the IR-side and the tow-body-side cable linkage is no longer transmitted by way of the woven flap 1 but by way of the cable piece 12 situated in-between. No connection exists between the woven flap 1 and the towing cable 6, which has the result that the woven flap 1 is dropped. It is therefore prevented that, after the conclusion of the reel-off operation, the woven flap 1, by beating on the towing cable 6, damages the latter or impairs the flying action of the IR flare. 

1. Tow body for the representation of flying targets by means of infrared flares, the infrared flares being situated at the rear of the tow body and being ejectable from the tow body and capable of being pulled by the tow body by means of towing cables during the burning time, characterized in that a section of the towing cable (6) situated between the IR-flare-side cable linkage (2) and the tow-body-side cable linkage (5) is sewn onto a woven flap (1), this connection being releasable during the reel-off operation of the towing cable (6).
 2. Tow body according to claim 1, characterized in that the towing cable (6) is sewn onto the woven flap (1) in a serpentine shape.
 3. Tow body according to claim 2, characterized in that the cable sections of the towing cable (6) which extend against the pulling direction of the IR flare are sewn to the woven flap (1).
 4. Tow body according to one of the preceding claims, characterized in that a tent-type eye (9) is formed in the woven flap (1) on the tow body side, for guiding through a retaining loop (4) for the woven flap (1), which retaining loop (4) is connected with the towing cable (6), and in that a towing cable loop (10) fixed on the woven flap (1) is guided through the retaining loop (4).
 5. Tow body according to one of the preceding claims, characterized in that the woven flap (1) is sewn to form a hose.
 6. Tow body according to one of the preceding claims, characterized in that the woven flap (1) has a fraction of polyamide.
 7. Tow body according to one or the preceding claims, characterized in that the towing cable (6) is a kevlar-coated polypropylene damping cable. 